| // SPDX-License-Identifier: GPL-2.0 |
| /* Multipath TCP |
| * |
| * Copyright (c) 2017 - 2019, Intel Corporation. |
| */ |
| |
| #define pr_fmt(fmt) "MPTCP: " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/netdevice.h> |
| #include <crypto/sha2.h> |
| #include <crypto/utils.h> |
| #include <net/sock.h> |
| #include <net/inet_common.h> |
| #include <net/inet_hashtables.h> |
| #include <net/protocol.h> |
| #include <net/tcp.h> |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| #include <net/ip6_route.h> |
| #include <net/transp_v6.h> |
| #endif |
| #include <net/mptcp.h> |
| #include <uapi/linux/mptcp.h> |
| #include "protocol.h" |
| #include "mib.h" |
| |
| #include <trace/events/mptcp.h> |
| #include <trace/events/sock.h> |
| |
| static void mptcp_subflow_ops_undo_override(struct sock *ssk); |
| |
| static void SUBFLOW_REQ_INC_STATS(struct request_sock *req, |
| enum linux_mptcp_mib_field field) |
| { |
| MPTCP_INC_STATS(sock_net(req_to_sk(req)), field); |
| } |
| |
| static void subflow_req_destructor(struct request_sock *req) |
| { |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| |
| pr_debug("subflow_req=%p", subflow_req); |
| |
| if (subflow_req->msk) |
| sock_put((struct sock *)subflow_req->msk); |
| |
| mptcp_token_destroy_request(req); |
| } |
| |
| static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2, |
| void *hmac) |
| { |
| u8 msg[8]; |
| |
| put_unaligned_be32(nonce1, &msg[0]); |
| put_unaligned_be32(nonce2, &msg[4]); |
| |
| mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac); |
| } |
| |
| static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk) |
| { |
| return mptcp_is_fully_established((void *)msk) && |
| ((mptcp_pm_is_userspace(msk) && |
| mptcp_userspace_pm_active(msk)) || |
| READ_ONCE(msk->pm.accept_subflow)); |
| } |
| |
| /* validate received token and create truncated hmac and nonce for SYN-ACK */ |
| static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req) |
| { |
| struct mptcp_sock *msk = subflow_req->msk; |
| u8 hmac[SHA256_DIGEST_SIZE]; |
| |
| get_random_bytes(&subflow_req->local_nonce, sizeof(u32)); |
| |
| subflow_generate_hmac(READ_ONCE(msk->local_key), |
| READ_ONCE(msk->remote_key), |
| subflow_req->local_nonce, |
| subflow_req->remote_nonce, hmac); |
| |
| subflow_req->thmac = get_unaligned_be64(hmac); |
| } |
| |
| static struct mptcp_sock *subflow_token_join_request(struct request_sock *req) |
| { |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| struct mptcp_sock *msk; |
| int local_id; |
| |
| msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token); |
| if (!msk) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN); |
| return NULL; |
| } |
| |
| local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req); |
| if (local_id < 0) { |
| sock_put((struct sock *)msk); |
| return NULL; |
| } |
| subflow_req->local_id = local_id; |
| |
| return msk; |
| } |
| |
| static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener) |
| { |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| |
| subflow_req->mp_capable = 0; |
| subflow_req->mp_join = 0; |
| subflow_req->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk_listener)); |
| subflow_req->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk_listener)); |
| subflow_req->msk = NULL; |
| mptcp_token_init_request(req); |
| } |
| |
| static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk) |
| { |
| return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport; |
| } |
| |
| static void subflow_add_reset_reason(struct sk_buff *skb, u8 reason) |
| { |
| struct mptcp_ext *mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
| |
| if (mpext) { |
| memset(mpext, 0, sizeof(*mpext)); |
| mpext->reset_reason = reason; |
| } |
| } |
| |
| /* Init mptcp request socket. |
| * |
| * Returns an error code if a JOIN has failed and a TCP reset |
| * should be sent. |
| */ |
| static int subflow_check_req(struct request_sock *req, |
| const struct sock *sk_listener, |
| struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| struct mptcp_options_received mp_opt; |
| bool opt_mp_capable, opt_mp_join; |
| |
| pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); |
| |
| #ifdef CONFIG_TCP_MD5SIG |
| /* no MPTCP if MD5SIG is enabled on this socket or we may run out of |
| * TCP option space. |
| */ |
| if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) |
| return -EINVAL; |
| #endif |
| |
| mptcp_get_options(skb, &mp_opt); |
| |
| opt_mp_capable = !!(mp_opt.suboptions & OPTION_MPTCP_MPC_SYN); |
| opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_SYN); |
| if (opt_mp_capable) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); |
| |
| if (opt_mp_join) |
| return 0; |
| } else if (opt_mp_join) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX); |
| } |
| |
| if (opt_mp_capable && listener->request_mptcp) { |
| int err, retries = MPTCP_TOKEN_MAX_RETRIES; |
| |
| subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
| again: |
| do { |
| get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key)); |
| } while (subflow_req->local_key == 0); |
| |
| if (unlikely(req->syncookie)) { |
| mptcp_crypto_key_sha(subflow_req->local_key, |
| &subflow_req->token, |
| &subflow_req->idsn); |
| if (mptcp_token_exists(subflow_req->token)) { |
| if (retries-- > 0) |
| goto again; |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); |
| } else { |
| subflow_req->mp_capable = 1; |
| } |
| return 0; |
| } |
| |
| err = mptcp_token_new_request(req); |
| if (err == 0) |
| subflow_req->mp_capable = 1; |
| else if (retries-- > 0) |
| goto again; |
| else |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); |
| |
| } else if (opt_mp_join && listener->request_mptcp) { |
| subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
| subflow_req->mp_join = 1; |
| subflow_req->backup = mp_opt.backup; |
| subflow_req->remote_id = mp_opt.join_id; |
| subflow_req->token = mp_opt.token; |
| subflow_req->remote_nonce = mp_opt.nonce; |
| subflow_req->msk = subflow_token_join_request(req); |
| |
| /* Can't fall back to TCP in this case. */ |
| if (!subflow_req->msk) { |
| subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); |
| return -EPERM; |
| } |
| |
| if (subflow_use_different_sport(subflow_req->msk, sk_listener)) { |
| pr_debug("syn inet_sport=%d %d", |
| ntohs(inet_sk(sk_listener)->inet_sport), |
| ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport)); |
| if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX); |
| return -EPERM; |
| } |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX); |
| } |
| |
| subflow_req_create_thmac(subflow_req); |
| |
| if (unlikely(req->syncookie)) { |
| if (mptcp_can_accept_new_subflow(subflow_req->msk)) |
| subflow_init_req_cookie_join_save(subflow_req, skb); |
| else |
| return -EPERM; |
| } |
| |
| pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, |
| subflow_req->remote_nonce, subflow_req->msk); |
| } |
| |
| return 0; |
| } |
| |
| int mptcp_subflow_init_cookie_req(struct request_sock *req, |
| const struct sock *sk_listener, |
| struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| struct mptcp_options_received mp_opt; |
| bool opt_mp_capable, opt_mp_join; |
| int err; |
| |
| subflow_init_req(req, sk_listener); |
| mptcp_get_options(skb, &mp_opt); |
| |
| opt_mp_capable = !!(mp_opt.suboptions & OPTION_MPTCP_MPC_ACK); |
| opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK); |
| if (opt_mp_capable && opt_mp_join) |
| return -EINVAL; |
| |
| if (opt_mp_capable && listener->request_mptcp) { |
| if (mp_opt.sndr_key == 0) |
| return -EINVAL; |
| |
| subflow_req->local_key = mp_opt.rcvr_key; |
| err = mptcp_token_new_request(req); |
| if (err) |
| return err; |
| |
| subflow_req->mp_capable = 1; |
| subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; |
| } else if (opt_mp_join && listener->request_mptcp) { |
| if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) |
| return -EINVAL; |
| |
| subflow_req->mp_join = 1; |
| subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req); |
| |
| static struct dst_entry *subflow_v4_route_req(const struct sock *sk, |
| struct sk_buff *skb, |
| struct flowi *fl, |
| struct request_sock *req) |
| { |
| struct dst_entry *dst; |
| int err; |
| |
| tcp_rsk(req)->is_mptcp = 1; |
| subflow_init_req(req, sk); |
| |
| dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req); |
| if (!dst) |
| return NULL; |
| |
| err = subflow_check_req(req, sk, skb); |
| if (err == 0) |
| return dst; |
| |
| dst_release(dst); |
| if (!req->syncookie) |
| tcp_request_sock_ops.send_reset(sk, skb); |
| return NULL; |
| } |
| |
| static void subflow_prep_synack(const struct sock *sk, struct request_sock *req, |
| struct tcp_fastopen_cookie *foc, |
| enum tcp_synack_type synack_type) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct inet_request_sock *ireq = inet_rsk(req); |
| |
| /* clear tstamp_ok, as needed depending on cookie */ |
| if (foc && foc->len > -1) |
| ireq->tstamp_ok = 0; |
| |
| if (synack_type == TCP_SYNACK_FASTOPEN) |
| mptcp_fastopen_subflow_synack_set_params(subflow, req); |
| } |
| |
| static int subflow_v4_send_synack(const struct sock *sk, struct dst_entry *dst, |
| struct flowi *fl, |
| struct request_sock *req, |
| struct tcp_fastopen_cookie *foc, |
| enum tcp_synack_type synack_type, |
| struct sk_buff *syn_skb) |
| { |
| subflow_prep_synack(sk, req, foc, synack_type); |
| |
| return tcp_request_sock_ipv4_ops.send_synack(sk, dst, fl, req, foc, |
| synack_type, syn_skb); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static int subflow_v6_send_synack(const struct sock *sk, struct dst_entry *dst, |
| struct flowi *fl, |
| struct request_sock *req, |
| struct tcp_fastopen_cookie *foc, |
| enum tcp_synack_type synack_type, |
| struct sk_buff *syn_skb) |
| { |
| subflow_prep_synack(sk, req, foc, synack_type); |
| |
| return tcp_request_sock_ipv6_ops.send_synack(sk, dst, fl, req, foc, |
| synack_type, syn_skb); |
| } |
| |
| static struct dst_entry *subflow_v6_route_req(const struct sock *sk, |
| struct sk_buff *skb, |
| struct flowi *fl, |
| struct request_sock *req) |
| { |
| struct dst_entry *dst; |
| int err; |
| |
| tcp_rsk(req)->is_mptcp = 1; |
| subflow_init_req(req, sk); |
| |
| dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req); |
| if (!dst) |
| return NULL; |
| |
| err = subflow_check_req(req, sk, skb); |
| if (err == 0) |
| return dst; |
| |
| dst_release(dst); |
| if (!req->syncookie) |
| tcp6_request_sock_ops.send_reset(sk, skb); |
| return NULL; |
| } |
| #endif |
| |
| /* validate received truncated hmac and create hmac for third ACK */ |
| static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow) |
| { |
| u8 hmac[SHA256_DIGEST_SIZE]; |
| u64 thmac; |
| |
| subflow_generate_hmac(subflow->remote_key, subflow->local_key, |
| subflow->remote_nonce, subflow->local_nonce, |
| hmac); |
| |
| thmac = get_unaligned_be64(hmac); |
| pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n", |
| subflow, subflow->token, thmac, subflow->thmac); |
| |
| return thmac == subflow->thmac; |
| } |
| |
| void mptcp_subflow_reset(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| struct sock *sk = subflow->conn; |
| |
| /* mptcp_mp_fail_no_response() can reach here on an already closed |
| * socket |
| */ |
| if (ssk->sk_state == TCP_CLOSE) |
| return; |
| |
| /* must hold: tcp_done() could drop last reference on parent */ |
| sock_hold(sk); |
| |
| tcp_send_active_reset(ssk, GFP_ATOMIC); |
| tcp_done(ssk); |
| if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags)) |
| mptcp_schedule_work(sk); |
| |
| sock_put(sk); |
| } |
| |
| static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk) |
| { |
| return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport; |
| } |
| |
| void __mptcp_sync_state(struct sock *sk, int state) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct sock *ssk = msk->first; |
| |
| subflow = mptcp_subflow_ctx(ssk); |
| __mptcp_propagate_sndbuf(sk, ssk); |
| if (!msk->rcvspace_init) |
| mptcp_rcv_space_init(msk, ssk); |
| |
| if (sk->sk_state == TCP_SYN_SENT) { |
| /* subflow->idsn is always available is TCP_SYN_SENT state, |
| * even for the FASTOPEN scenarios |
| */ |
| WRITE_ONCE(msk->write_seq, subflow->idsn + 1); |
| WRITE_ONCE(msk->snd_nxt, msk->write_seq); |
| mptcp_set_state(sk, state); |
| sk->sk_state_change(sk); |
| } |
| } |
| |
| static void subflow_set_remote_key(struct mptcp_sock *msk, |
| struct mptcp_subflow_context *subflow, |
| const struct mptcp_options_received *mp_opt) |
| { |
| /* active MPC subflow will reach here multiple times: |
| * at subflow_finish_connect() time and at 4th ack time |
| */ |
| if (subflow->remote_key_valid) |
| return; |
| |
| subflow->remote_key_valid = 1; |
| subflow->remote_key = mp_opt->sndr_key; |
| mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn); |
| subflow->iasn++; |
| |
| WRITE_ONCE(msk->remote_key, subflow->remote_key); |
| WRITE_ONCE(msk->ack_seq, subflow->iasn); |
| WRITE_ONCE(msk->can_ack, true); |
| atomic64_set(&msk->rcv_wnd_sent, subflow->iasn); |
| } |
| |
| static void mptcp_propagate_state(struct sock *sk, struct sock *ssk, |
| struct mptcp_subflow_context *subflow, |
| const struct mptcp_options_received *mp_opt) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| mptcp_data_lock(sk); |
| if (mp_opt) { |
| /* Options are available only in the non fallback cases |
| * avoid updating rx path fields otherwise |
| */ |
| WRITE_ONCE(msk->snd_una, subflow->idsn + 1); |
| WRITE_ONCE(msk->wnd_end, subflow->idsn + 1 + tcp_sk(ssk)->snd_wnd); |
| subflow_set_remote_key(msk, subflow, mp_opt); |
| } |
| |
| if (!sock_owned_by_user(sk)) { |
| __mptcp_sync_state(sk, ssk->sk_state); |
| } else { |
| msk->pending_state = ssk->sk_state; |
| __set_bit(MPTCP_SYNC_STATE, &msk->cb_flags); |
| } |
| mptcp_data_unlock(sk); |
| } |
| |
| static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct mptcp_options_received mp_opt; |
| struct sock *parent = subflow->conn; |
| struct mptcp_sock *msk; |
| |
| subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); |
| |
| /* be sure no special action on any packet other than syn-ack */ |
| if (subflow->conn_finished) |
| return; |
| |
| msk = mptcp_sk(parent); |
| subflow->rel_write_seq = 1; |
| subflow->conn_finished = 1; |
| subflow->ssn_offset = TCP_SKB_CB(skb)->seq; |
| pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset); |
| |
| mptcp_get_options(skb, &mp_opt); |
| if (subflow->request_mptcp) { |
| if (!(mp_opt.suboptions & OPTION_MPTCP_MPC_SYNACK)) { |
| MPTCP_INC_STATS(sock_net(sk), |
| MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); |
| mptcp_do_fallback(sk); |
| pr_fallback(msk); |
| goto fallback; |
| } |
| |
| if (mp_opt.suboptions & OPTION_MPTCP_CSUMREQD) |
| WRITE_ONCE(msk->csum_enabled, true); |
| if (mp_opt.deny_join_id0) |
| WRITE_ONCE(msk->pm.remote_deny_join_id0, true); |
| subflow->mp_capable = 1; |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEACK); |
| mptcp_finish_connect(sk); |
| mptcp_propagate_state(parent, sk, subflow, &mp_opt); |
| } else if (subflow->request_join) { |
| u8 hmac[SHA256_DIGEST_SIZE]; |
| |
| if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_SYNACK)) { |
| subflow->reset_reason = MPTCP_RST_EMPTCP; |
| goto do_reset; |
| } |
| |
| subflow->backup = mp_opt.backup; |
| subflow->thmac = mp_opt.thmac; |
| subflow->remote_nonce = mp_opt.nonce; |
| WRITE_ONCE(subflow->remote_id, mp_opt.join_id); |
| pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u backup=%d", |
| subflow, subflow->thmac, subflow->remote_nonce, |
| subflow->backup); |
| |
| if (!subflow_thmac_valid(subflow)) { |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC); |
| subflow->reset_reason = MPTCP_RST_EMPTCP; |
| goto do_reset; |
| } |
| |
| if (!mptcp_finish_join(sk)) |
| goto do_reset; |
| |
| subflow_generate_hmac(subflow->local_key, subflow->remote_key, |
| subflow->local_nonce, |
| subflow->remote_nonce, |
| hmac); |
| memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN); |
| |
| subflow->mp_join = 1; |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX); |
| |
| if (subflow_use_different_dport(msk, sk)) { |
| pr_debug("synack inet_dport=%d %d", |
| ntohs(inet_sk(sk)->inet_dport), |
| ntohs(inet_sk(parent)->inet_dport)); |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX); |
| } |
| } else if (mptcp_check_fallback(sk)) { |
| fallback: |
| mptcp_propagate_state(parent, sk, subflow, NULL); |
| } |
| return; |
| |
| do_reset: |
| subflow->reset_transient = 0; |
| mptcp_subflow_reset(sk); |
| } |
| |
| static void subflow_set_local_id(struct mptcp_subflow_context *subflow, int local_id) |
| { |
| WARN_ON_ONCE(local_id < 0 || local_id > 255); |
| WRITE_ONCE(subflow->local_id, local_id); |
| } |
| |
| static int subflow_chk_local_id(struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| int err; |
| |
| if (likely(subflow->local_id >= 0)) |
| return 0; |
| |
| err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk); |
| if (err < 0) |
| return err; |
| |
| subflow_set_local_id(subflow, err); |
| return 0; |
| } |
| |
| static int subflow_rebuild_header(struct sock *sk) |
| { |
| int err = subflow_chk_local_id(sk); |
| |
| if (unlikely(err < 0)) |
| return err; |
| |
| return inet_sk_rebuild_header(sk); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static int subflow_v6_rebuild_header(struct sock *sk) |
| { |
| int err = subflow_chk_local_id(sk); |
| |
| if (unlikely(err < 0)) |
| return err; |
| |
| return inet6_sk_rebuild_header(sk); |
| } |
| #endif |
| |
| static struct request_sock_ops mptcp_subflow_v4_request_sock_ops __ro_after_init; |
| static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init; |
| |
| static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| |
| pr_debug("subflow=%p", subflow); |
| |
| /* Never answer to SYNs sent to broadcast or multicast */ |
| if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) |
| goto drop; |
| |
| return tcp_conn_request(&mptcp_subflow_v4_request_sock_ops, |
| &subflow_request_sock_ipv4_ops, |
| sk, skb); |
| drop: |
| tcp_listendrop(sk); |
| return 0; |
| } |
| |
| static void subflow_v4_req_destructor(struct request_sock *req) |
| { |
| subflow_req_destructor(req); |
| tcp_request_sock_ops.destructor(req); |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init; |
| static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init; |
| static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init; |
| static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init; |
| static struct proto tcpv6_prot_override __ro_after_init; |
| |
| static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| |
| pr_debug("subflow=%p", subflow); |
| |
| if (skb->protocol == htons(ETH_P_IP)) |
| return subflow_v4_conn_request(sk, skb); |
| |
| if (!ipv6_unicast_destination(skb)) |
| goto drop; |
| |
| if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { |
| __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); |
| return 0; |
| } |
| |
| return tcp_conn_request(&mptcp_subflow_v6_request_sock_ops, |
| &subflow_request_sock_ipv6_ops, sk, skb); |
| |
| drop: |
| tcp_listendrop(sk); |
| return 0; /* don't send reset */ |
| } |
| |
| static void subflow_v6_req_destructor(struct request_sock *req) |
| { |
| subflow_req_destructor(req); |
| tcp6_request_sock_ops.destructor(req); |
| } |
| #endif |
| |
| struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops, |
| struct sock *sk_listener, |
| bool attach_listener) |
| { |
| if (ops->family == AF_INET) |
| ops = &mptcp_subflow_v4_request_sock_ops; |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else if (ops->family == AF_INET6) |
| ops = &mptcp_subflow_v6_request_sock_ops; |
| #endif |
| |
| return inet_reqsk_alloc(ops, sk_listener, attach_listener); |
| } |
| EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc); |
| |
| /* validate hmac received in third ACK */ |
| static bool subflow_hmac_valid(const struct request_sock *req, |
| const struct mptcp_options_received *mp_opt) |
| { |
| const struct mptcp_subflow_request_sock *subflow_req; |
| u8 hmac[SHA256_DIGEST_SIZE]; |
| struct mptcp_sock *msk; |
| |
| subflow_req = mptcp_subflow_rsk(req); |
| msk = subflow_req->msk; |
| if (!msk) |
| return false; |
| |
| subflow_generate_hmac(READ_ONCE(msk->remote_key), |
| READ_ONCE(msk->local_key), |
| subflow_req->remote_nonce, |
| subflow_req->local_nonce, hmac); |
| |
| return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN); |
| } |
| |
| static void subflow_ulp_fallback(struct sock *sk, |
| struct mptcp_subflow_context *old_ctx) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| mptcp_subflow_tcp_fallback(sk, old_ctx); |
| icsk->icsk_ulp_ops = NULL; |
| rcu_assign_pointer(icsk->icsk_ulp_data, NULL); |
| tcp_sk(sk)->is_mptcp = 0; |
| |
| mptcp_subflow_ops_undo_override(sk); |
| } |
| |
| void mptcp_subflow_drop_ctx(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); |
| |
| if (!ctx) |
| return; |
| |
| list_del(&mptcp_subflow_ctx(ssk)->node); |
| if (inet_csk(ssk)->icsk_ulp_ops) { |
| subflow_ulp_fallback(ssk, ctx); |
| if (ctx->conn) |
| sock_put(ctx->conn); |
| } |
| |
| kfree_rcu(ctx, rcu); |
| } |
| |
| void __mptcp_subflow_fully_established(struct mptcp_sock *msk, |
| struct mptcp_subflow_context *subflow, |
| const struct mptcp_options_received *mp_opt) |
| { |
| subflow_set_remote_key(msk, subflow, mp_opt); |
| subflow->fully_established = 1; |
| WRITE_ONCE(msk->fully_established, true); |
| |
| if (subflow->is_mptfo) |
| __mptcp_fastopen_gen_msk_ackseq(msk, subflow, mp_opt); |
| } |
| |
| static struct sock *subflow_syn_recv_sock(const struct sock *sk, |
| struct sk_buff *skb, |
| struct request_sock *req, |
| struct dst_entry *dst, |
| struct request_sock *req_unhash, |
| bool *own_req) |
| { |
| struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk); |
| struct mptcp_subflow_request_sock *subflow_req; |
| struct mptcp_options_received mp_opt; |
| bool fallback, fallback_is_fatal; |
| struct mptcp_sock *owner; |
| struct sock *child; |
| |
| pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn); |
| |
| /* After child creation we must look for MPC even when options |
| * are not parsed |
| */ |
| mp_opt.suboptions = 0; |
| |
| /* hopefully temporary handling for MP_JOIN+syncookie */ |
| subflow_req = mptcp_subflow_rsk(req); |
| fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join; |
| fallback = !tcp_rsk(req)->is_mptcp; |
| if (fallback) |
| goto create_child; |
| |
| /* if the sk is MP_CAPABLE, we try to fetch the client key */ |
| if (subflow_req->mp_capable) { |
| /* we can receive and accept an in-window, out-of-order pkt, |
| * which may not carry the MP_CAPABLE opt even on mptcp enabled |
| * paths: always try to extract the peer key, and fallback |
| * for packets missing it. |
| * Even OoO DSS packets coming legitly after dropped or |
| * reordered MPC will cause fallback, but we don't have other |
| * options. |
| */ |
| mptcp_get_options(skb, &mp_opt); |
| if (!(mp_opt.suboptions & |
| (OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_ACK))) |
| fallback = true; |
| |
| } else if (subflow_req->mp_join) { |
| mptcp_get_options(skb, &mp_opt); |
| if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK) || |
| !subflow_hmac_valid(req, &mp_opt) || |
| !mptcp_can_accept_new_subflow(subflow_req->msk)) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); |
| fallback = true; |
| } |
| } |
| |
| create_child: |
| child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, |
| req_unhash, own_req); |
| |
| if (child && *own_req) { |
| struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child); |
| |
| tcp_rsk(req)->drop_req = false; |
| |
| /* we need to fallback on ctx allocation failure and on pre-reqs |
| * checking above. In the latter scenario we additionally need |
| * to reset the context to non MPTCP status. |
| */ |
| if (!ctx || fallback) { |
| if (fallback_is_fatal) { |
| subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); |
| goto dispose_child; |
| } |
| goto fallback; |
| } |
| |
| /* ssk inherits options of listener sk */ |
| ctx->setsockopt_seq = listener->setsockopt_seq; |
| |
| if (ctx->mp_capable) { |
| ctx->conn = mptcp_sk_clone_init(listener->conn, &mp_opt, child, req); |
| if (!ctx->conn) |
| goto fallback; |
| |
| ctx->subflow_id = 1; |
| owner = mptcp_sk(ctx->conn); |
| mptcp_pm_new_connection(owner, child, 1); |
| |
| /* with OoO packets we can reach here without ingress |
| * mpc option |
| */ |
| if (mp_opt.suboptions & OPTION_MPTCP_MPC_ACK) { |
| mptcp_pm_fully_established(owner, child); |
| ctx->pm_notified = 1; |
| } |
| } else if (ctx->mp_join) { |
| owner = subflow_req->msk; |
| if (!owner) { |
| subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); |
| goto dispose_child; |
| } |
| |
| /* move the msk reference ownership to the subflow */ |
| subflow_req->msk = NULL; |
| ctx->conn = (struct sock *)owner; |
| |
| if (subflow_use_different_sport(owner, sk)) { |
| pr_debug("ack inet_sport=%d %d", |
| ntohs(inet_sk(sk)->inet_sport), |
| ntohs(inet_sk((struct sock *)owner)->inet_sport)); |
| if (!mptcp_pm_sport_in_anno_list(owner, sk)) { |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX); |
| goto dispose_child; |
| } |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX); |
| } |
| |
| if (!mptcp_finish_join(child)) |
| goto dispose_child; |
| |
| SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX); |
| tcp_rsk(req)->drop_req = true; |
| } |
| } |
| |
| /* check for expected invariant - should never trigger, just help |
| * catching eariler subtle bugs |
| */ |
| WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp && |
| (!mptcp_subflow_ctx(child) || |
| !mptcp_subflow_ctx(child)->conn)); |
| return child; |
| |
| dispose_child: |
| mptcp_subflow_drop_ctx(child); |
| tcp_rsk(req)->drop_req = true; |
| inet_csk_prepare_for_destroy_sock(child); |
| tcp_done(child); |
| req->rsk_ops->send_reset(sk, skb); |
| |
| /* The last child reference will be released by the caller */ |
| return child; |
| |
| fallback: |
| mptcp_subflow_drop_ctx(child); |
| return child; |
| } |
| |
| static struct inet_connection_sock_af_ops subflow_specific __ro_after_init; |
| static struct proto tcp_prot_override __ro_after_init; |
| |
| enum mapping_status { |
| MAPPING_OK, |
| MAPPING_INVALID, |
| MAPPING_EMPTY, |
| MAPPING_DATA_FIN, |
| MAPPING_DUMMY, |
| MAPPING_BAD_CSUM |
| }; |
| |
| static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) |
| { |
| pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d", |
| ssn, subflow->map_subflow_seq, subflow->map_data_len); |
| } |
| |
| static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| unsigned int skb_consumed; |
| |
| skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; |
| if (WARN_ON_ONCE(skb_consumed >= skb->len)) |
| return true; |
| |
| return skb->len - skb_consumed <= subflow->map_data_len - |
| mptcp_subflow_get_map_offset(subflow); |
| } |
| |
| static bool validate_mapping(struct sock *ssk, struct sk_buff *skb) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; |
| |
| if (unlikely(before(ssn, subflow->map_subflow_seq))) { |
| /* Mapping covers data later in the subflow stream, |
| * currently unsupported. |
| */ |
| dbg_bad_map(subflow, ssn); |
| return false; |
| } |
| if (unlikely(!before(ssn, subflow->map_subflow_seq + |
| subflow->map_data_len))) { |
| /* Mapping does covers past subflow data, invalid */ |
| dbg_bad_map(subflow, ssn); |
| return false; |
| } |
| return true; |
| } |
| |
| static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *skb, |
| bool csum_reqd) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| u32 offset, seq, delta; |
| __sum16 csum; |
| int len; |
| |
| if (!csum_reqd) |
| return MAPPING_OK; |
| |
| /* mapping already validated on previous traversal */ |
| if (subflow->map_csum_len == subflow->map_data_len) |
| return MAPPING_OK; |
| |
| /* traverse the receive queue, ensuring it contains a full |
| * DSS mapping and accumulating the related csum. |
| * Preserve the accoumlate csum across multiple calls, to compute |
| * the csum only once |
| */ |
| delta = subflow->map_data_len - subflow->map_csum_len; |
| for (;;) { |
| seq = tcp_sk(ssk)->copied_seq + subflow->map_csum_len; |
| offset = seq - TCP_SKB_CB(skb)->seq; |
| |
| /* if the current skb has not been accounted yet, csum its contents |
| * up to the amount covered by the current DSS |
| */ |
| if (offset < skb->len) { |
| __wsum csum; |
| |
| len = min(skb->len - offset, delta); |
| csum = skb_checksum(skb, offset, len, 0); |
| subflow->map_data_csum = csum_block_add(subflow->map_data_csum, csum, |
| subflow->map_csum_len); |
| |
| delta -= len; |
| subflow->map_csum_len += len; |
| } |
| if (delta == 0) |
| break; |
| |
| if (skb_queue_is_last(&ssk->sk_receive_queue, skb)) { |
| /* if this subflow is closed, the partial mapping |
| * will be never completed; flush the pending skbs, so |
| * that subflow_sched_work_if_closed() can kick in |
| */ |
| if (unlikely(ssk->sk_state == TCP_CLOSE)) |
| while ((skb = skb_peek(&ssk->sk_receive_queue))) |
| sk_eat_skb(ssk, skb); |
| |
| /* not enough data to validate the csum */ |
| return MAPPING_EMPTY; |
| } |
| |
| /* the DSS mapping for next skbs will be validated later, |
| * when a get_mapping_status call will process such skb |
| */ |
| skb = skb->next; |
| } |
| |
| /* note that 'map_data_len' accounts only for the carried data, does |
| * not include the eventual seq increment due to the data fin, |
| * while the pseudo header requires the original DSS data len, |
| * including that |
| */ |
| csum = __mptcp_make_csum(subflow->map_seq, |
| subflow->map_subflow_seq, |
| subflow->map_data_len + subflow->map_data_fin, |
| subflow->map_data_csum); |
| if (unlikely(csum)) { |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR); |
| return MAPPING_BAD_CSUM; |
| } |
| |
| subflow->valid_csum_seen = 1; |
| return MAPPING_OK; |
| } |
| |
| static enum mapping_status get_mapping_status(struct sock *ssk, |
| struct mptcp_sock *msk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| bool csum_reqd = READ_ONCE(msk->csum_enabled); |
| struct mptcp_ext *mpext; |
| struct sk_buff *skb; |
| u16 data_len; |
| u64 map_seq; |
| |
| skb = skb_peek(&ssk->sk_receive_queue); |
| if (!skb) |
| return MAPPING_EMPTY; |
| |
| if (mptcp_check_fallback(ssk)) |
| return MAPPING_DUMMY; |
| |
| mpext = mptcp_get_ext(skb); |
| if (!mpext || !mpext->use_map) { |
| if (!subflow->map_valid && !skb->len) { |
| /* the TCP stack deliver 0 len FIN pkt to the receive |
| * queue, that is the only 0len pkts ever expected here, |
| * and we can admit no mapping only for 0 len pkts |
| */ |
| if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) |
| WARN_ONCE(1, "0len seq %d:%d flags %x", |
| TCP_SKB_CB(skb)->seq, |
| TCP_SKB_CB(skb)->end_seq, |
| TCP_SKB_CB(skb)->tcp_flags); |
| sk_eat_skb(ssk, skb); |
| return MAPPING_EMPTY; |
| } |
| |
| if (!subflow->map_valid) |
| return MAPPING_INVALID; |
| |
| goto validate_seq; |
| } |
| |
| trace_get_mapping_status(mpext); |
| |
| data_len = mpext->data_len; |
| if (data_len == 0) { |
| pr_debug("infinite mapping received"); |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX); |
| subflow->map_data_len = 0; |
| return MAPPING_INVALID; |
| } |
| |
| if (mpext->data_fin == 1) { |
| if (data_len == 1) { |
| bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq, |
| mpext->dsn64); |
| pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq); |
| if (subflow->map_valid) { |
| /* A DATA_FIN might arrive in a DSS |
| * option before the previous mapping |
| * has been fully consumed. Continue |
| * handling the existing mapping. |
| */ |
| skb_ext_del(skb, SKB_EXT_MPTCP); |
| return MAPPING_OK; |
| } else { |
| if (updated) |
| mptcp_schedule_work((struct sock *)msk); |
| |
| return MAPPING_DATA_FIN; |
| } |
| } else { |
| u64 data_fin_seq = mpext->data_seq + data_len - 1; |
| |
| /* If mpext->data_seq is a 32-bit value, data_fin_seq |
| * must also be limited to 32 bits. |
| */ |
| if (!mpext->dsn64) |
| data_fin_seq &= GENMASK_ULL(31, 0); |
| |
| mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64); |
| pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d", |
| data_fin_seq, mpext->dsn64); |
| } |
| |
| /* Adjust for DATA_FIN using 1 byte of sequence space */ |
| data_len--; |
| } |
| |
| map_seq = mptcp_expand_seq(READ_ONCE(msk->ack_seq), mpext->data_seq, mpext->dsn64); |
| WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64); |
| |
| if (subflow->map_valid) { |
| /* Allow replacing only with an identical map */ |
| if (subflow->map_seq == map_seq && |
| subflow->map_subflow_seq == mpext->subflow_seq && |
| subflow->map_data_len == data_len && |
| subflow->map_csum_reqd == mpext->csum_reqd) { |
| skb_ext_del(skb, SKB_EXT_MPTCP); |
| goto validate_csum; |
| } |
| |
| /* If this skb data are fully covered by the current mapping, |
| * the new map would need caching, which is not supported |
| */ |
| if (skb_is_fully_mapped(ssk, skb)) { |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH); |
| return MAPPING_INVALID; |
| } |
| |
| /* will validate the next map after consuming the current one */ |
| goto validate_csum; |
| } |
| |
| subflow->map_seq = map_seq; |
| subflow->map_subflow_seq = mpext->subflow_seq; |
| subflow->map_data_len = data_len; |
| subflow->map_valid = 1; |
| subflow->map_data_fin = mpext->data_fin; |
| subflow->mpc_map = mpext->mpc_map; |
| subflow->map_csum_reqd = mpext->csum_reqd; |
| subflow->map_csum_len = 0; |
| subflow->map_data_csum = csum_unfold(mpext->csum); |
| |
| /* Cfr RFC 8684 Section 3.3.0 */ |
| if (unlikely(subflow->map_csum_reqd != csum_reqd)) |
| return MAPPING_INVALID; |
| |
| pr_debug("new map seq=%llu subflow_seq=%u data_len=%u csum=%d:%u", |
| subflow->map_seq, subflow->map_subflow_seq, |
| subflow->map_data_len, subflow->map_csum_reqd, |
| subflow->map_data_csum); |
| |
| validate_seq: |
| /* we revalidate valid mapping on new skb, because we must ensure |
| * the current skb is completely covered by the available mapping |
| */ |
| if (!validate_mapping(ssk, skb)) { |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSTCPMISMATCH); |
| return MAPPING_INVALID; |
| } |
| |
| skb_ext_del(skb, SKB_EXT_MPTCP); |
| |
| validate_csum: |
| return validate_data_csum(ssk, skb, csum_reqd); |
| } |
| |
| static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb, |
| u64 limit) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; |
| u32 incr; |
| |
| incr = limit >= skb->len ? skb->len + fin : limit; |
| |
| pr_debug("discarding=%d len=%d seq=%d", incr, skb->len, |
| subflow->map_subflow_seq); |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA); |
| tcp_sk(ssk)->copied_seq += incr; |
| if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq)) |
| sk_eat_skb(ssk, skb); |
| if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) |
| subflow->map_valid = 0; |
| } |
| |
| /* sched mptcp worker to remove the subflow if no more data is pending */ |
| static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk) |
| { |
| if (likely(ssk->sk_state != TCP_CLOSE)) |
| return; |
| |
| if (skb_queue_empty(&ssk->sk_receive_queue) && |
| !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) |
| mptcp_schedule_work((struct sock *)msk); |
| } |
| |
| static bool subflow_can_fallback(struct mptcp_subflow_context *subflow) |
| { |
| struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| |
| if (subflow->mp_join) |
| return false; |
| else if (READ_ONCE(msk->csum_enabled)) |
| return !subflow->valid_csum_seen; |
| else |
| return !subflow->fully_established; |
| } |
| |
| static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| unsigned long fail_tout; |
| |
| /* greceful failure can happen only on the MPC subflow */ |
| if (WARN_ON_ONCE(ssk != READ_ONCE(msk->first))) |
| return; |
| |
| /* since the close timeout take precedence on the fail one, |
| * no need to start the latter when the first is already set |
| */ |
| if (sock_flag((struct sock *)msk, SOCK_DEAD)) |
| return; |
| |
| /* we don't need extreme accuracy here, use a zero fail_tout as special |
| * value meaning no fail timeout at all; |
| */ |
| fail_tout = jiffies + TCP_RTO_MAX; |
| if (!fail_tout) |
| fail_tout = 1; |
| WRITE_ONCE(subflow->fail_tout, fail_tout); |
| tcp_send_ack(ssk); |
| |
| mptcp_reset_tout_timer(msk, subflow->fail_tout); |
| } |
| |
| static bool subflow_check_data_avail(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| enum mapping_status status; |
| struct mptcp_sock *msk; |
| struct sk_buff *skb; |
| |
| if (!skb_peek(&ssk->sk_receive_queue)) |
| WRITE_ONCE(subflow->data_avail, false); |
| if (subflow->data_avail) |
| return true; |
| |
| msk = mptcp_sk(subflow->conn); |
| for (;;) { |
| u64 ack_seq; |
| u64 old_ack; |
| |
| status = get_mapping_status(ssk, msk); |
| trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue)); |
| if (unlikely(status == MAPPING_INVALID || status == MAPPING_DUMMY || |
| status == MAPPING_BAD_CSUM)) |
| goto fallback; |
| |
| if (status != MAPPING_OK) |
| goto no_data; |
| |
| skb = skb_peek(&ssk->sk_receive_queue); |
| if (WARN_ON_ONCE(!skb)) |
| goto no_data; |
| |
| if (unlikely(!READ_ONCE(msk->can_ack))) |
| goto fallback; |
| |
| old_ack = READ_ONCE(msk->ack_seq); |
| ack_seq = mptcp_subflow_get_mapped_dsn(subflow); |
| pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack, |
| ack_seq); |
| if (unlikely(before64(ack_seq, old_ack))) { |
| mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq); |
| continue; |
| } |
| |
| WRITE_ONCE(subflow->data_avail, true); |
| break; |
| } |
| return true; |
| |
| no_data: |
| subflow_sched_work_if_closed(msk, ssk); |
| return false; |
| |
| fallback: |
| if (!__mptcp_check_fallback(msk)) { |
| /* RFC 8684 section 3.7. */ |
| if (status == MAPPING_BAD_CSUM && |
| (subflow->mp_join || subflow->valid_csum_seen)) { |
| subflow->send_mp_fail = 1; |
| |
| if (!READ_ONCE(msk->allow_infinite_fallback)) { |
| subflow->reset_transient = 0; |
| subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; |
| goto reset; |
| } |
| mptcp_subflow_fail(msk, ssk); |
| WRITE_ONCE(subflow->data_avail, true); |
| return true; |
| } |
| |
| if (!subflow_can_fallback(subflow) && subflow->map_data_len) { |
| /* fatal protocol error, close the socket. |
| * subflow_error_report() will introduce the appropriate barriers |
| */ |
| subflow->reset_transient = 0; |
| subflow->reset_reason = MPTCP_RST_EMPTCP; |
| |
| reset: |
| WRITE_ONCE(ssk->sk_err, EBADMSG); |
| tcp_set_state(ssk, TCP_CLOSE); |
| while ((skb = skb_peek(&ssk->sk_receive_queue))) |
| sk_eat_skb(ssk, skb); |
| tcp_send_active_reset(ssk, GFP_ATOMIC); |
| WRITE_ONCE(subflow->data_avail, false); |
| return false; |
| } |
| |
| mptcp_do_fallback(ssk); |
| } |
| |
| skb = skb_peek(&ssk->sk_receive_queue); |
| subflow->map_valid = 1; |
| subflow->map_seq = READ_ONCE(msk->ack_seq); |
| subflow->map_data_len = skb->len; |
| subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; |
| WRITE_ONCE(subflow->data_avail, true); |
| return true; |
| } |
| |
| bool mptcp_subflow_data_available(struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| |
| /* check if current mapping is still valid */ |
| if (subflow->map_valid && |
| mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) { |
| subflow->map_valid = 0; |
| WRITE_ONCE(subflow->data_avail, false); |
| |
| pr_debug("Done with mapping: seq=%u data_len=%u", |
| subflow->map_subflow_seq, |
| subflow->map_data_len); |
| } |
| |
| return subflow_check_data_avail(sk); |
| } |
| |
| /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy, |
| * not the ssk one. |
| * |
| * In mptcp, rwin is about the mptcp-level connection data. |
| * |
| * Data that is still on the ssk rx queue can thus be ignored, |
| * as far as mptcp peer is concerned that data is still inflight. |
| * DSS ACK is updated when skb is moved to the mptcp rx queue. |
| */ |
| void mptcp_space(const struct sock *ssk, int *space, int *full_space) |
| { |
| const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| const struct sock *sk = subflow->conn; |
| |
| *space = __mptcp_space(sk); |
| *full_space = mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); |
| } |
| |
| static void subflow_error_report(struct sock *ssk) |
| { |
| struct sock *sk = mptcp_subflow_ctx(ssk)->conn; |
| |
| /* bail early if this is a no-op, so that we avoid introducing a |
| * problematic lockdep dependency between TCP accept queue lock |
| * and msk socket spinlock |
| */ |
| if (!sk->sk_socket) |
| return; |
| |
| mptcp_data_lock(sk); |
| if (!sock_owned_by_user(sk)) |
| __mptcp_error_report(sk); |
| else |
| __set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->cb_flags); |
| mptcp_data_unlock(sk); |
| } |
| |
| static void subflow_data_ready(struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| u16 state = 1 << inet_sk_state_load(sk); |
| struct sock *parent = subflow->conn; |
| struct mptcp_sock *msk; |
| |
| trace_sk_data_ready(sk); |
| |
| msk = mptcp_sk(parent); |
| if (state & TCPF_LISTEN) { |
| /* MPJ subflow are removed from accept queue before reaching here, |
| * avoid stray wakeups |
| */ |
| if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue)) |
| return; |
| |
| parent->sk_data_ready(parent); |
| return; |
| } |
| |
| WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable && |
| !subflow->mp_join && !(state & TCPF_CLOSE)); |
| |
| if (mptcp_subflow_data_available(sk)) { |
| mptcp_data_ready(parent, sk); |
| |
| /* subflow-level lowat test are not relevant. |
| * respect the msk-level threshold eventually mandating an immediate ack |
| */ |
| if (mptcp_data_avail(msk) < parent->sk_rcvlowat && |
| (tcp_sk(sk)->rcv_nxt - tcp_sk(sk)->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss) |
| inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; |
| } else if (unlikely(sk->sk_err)) { |
| subflow_error_report(sk); |
| } |
| } |
| |
| static void subflow_write_space(struct sock *ssk) |
| { |
| struct sock *sk = mptcp_subflow_ctx(ssk)->conn; |
| |
| mptcp_propagate_sndbuf(sk, ssk); |
| mptcp_write_space(sk); |
| } |
| |
| static const struct inet_connection_sock_af_ops * |
| subflow_default_af_ops(struct sock *sk) |
| { |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| if (sk->sk_family == AF_INET6) |
| return &subflow_v6_specific; |
| #endif |
| return &subflow_specific; |
| } |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| void mptcpv6_handle_mapped(struct sock *sk, bool mapped) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| const struct inet_connection_sock_af_ops *target; |
| |
| target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk); |
| |
| pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d", |
| subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped); |
| |
| if (likely(icsk->icsk_af_ops == target)) |
| return; |
| |
| subflow->icsk_af_ops = icsk->icsk_af_ops; |
| icsk->icsk_af_ops = target; |
| } |
| #endif |
| |
| void mptcp_info2sockaddr(const struct mptcp_addr_info *info, |
| struct sockaddr_storage *addr, |
| unsigned short family) |
| { |
| memset(addr, 0, sizeof(*addr)); |
| addr->ss_family = family; |
| if (addr->ss_family == AF_INET) { |
| struct sockaddr_in *in_addr = (struct sockaddr_in *)addr; |
| |
| if (info->family == AF_INET) |
| in_addr->sin_addr = info->addr; |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else if (ipv6_addr_v4mapped(&info->addr6)) |
| in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3]; |
| #endif |
| in_addr->sin_port = info->port; |
| } |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else if (addr->ss_family == AF_INET6) { |
| struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr; |
| |
| if (info->family == AF_INET) |
| ipv6_addr_set_v4mapped(info->addr.s_addr, |
| &in6_addr->sin6_addr); |
| else |
| in6_addr->sin6_addr = info->addr6; |
| in6_addr->sin6_port = info->port; |
| } |
| #endif |
| } |
| |
| int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, |
| const struct mptcp_addr_info *remote) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct mptcp_subflow_context *subflow; |
| struct sockaddr_storage addr; |
| int remote_id = remote->id; |
| int local_id = loc->id; |
| int err = -ENOTCONN; |
| struct socket *sf; |
| struct sock *ssk; |
| u32 remote_token; |
| int addrlen; |
| int ifindex; |
| u8 flags; |
| |
| if (!mptcp_is_fully_established(sk)) |
| goto err_out; |
| |
| err = mptcp_subflow_create_socket(sk, loc->family, &sf); |
| if (err) |
| goto err_out; |
| |
| ssk = sf->sk; |
| subflow = mptcp_subflow_ctx(ssk); |
| do { |
| get_random_bytes(&subflow->local_nonce, sizeof(u32)); |
| } while (!subflow->local_nonce); |
| |
| if (local_id) |
| subflow_set_local_id(subflow, local_id); |
| |
| mptcp_pm_get_flags_and_ifindex_by_id(msk, local_id, |
| &flags, &ifindex); |
| subflow->remote_key_valid = 1; |
| subflow->remote_key = READ_ONCE(msk->remote_key); |
| subflow->local_key = READ_ONCE(msk->local_key); |
| subflow->token = msk->token; |
| mptcp_info2sockaddr(loc, &addr, ssk->sk_family); |
| |
| addrlen = sizeof(struct sockaddr_in); |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| if (addr.ss_family == AF_INET6) |
| addrlen = sizeof(struct sockaddr_in6); |
| #endif |
| ssk->sk_bound_dev_if = ifindex; |
| err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen); |
| if (err) |
| goto failed; |
| |
| mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL); |
| pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk, |
| remote_token, local_id, remote_id); |
| subflow->remote_token = remote_token; |
| WRITE_ONCE(subflow->remote_id, remote_id); |
| subflow->request_join = 1; |
| subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP); |
| subflow->subflow_id = msk->subflow_id++; |
| mptcp_info2sockaddr(remote, &addr, ssk->sk_family); |
| |
| sock_hold(ssk); |
| list_add_tail(&subflow->node, &msk->conn_list); |
| err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK); |
| if (err && err != -EINPROGRESS) |
| goto failed_unlink; |
| |
| /* discard the subflow socket */ |
| mptcp_sock_graft(ssk, sk->sk_socket); |
| iput(SOCK_INODE(sf)); |
| WRITE_ONCE(msk->allow_infinite_fallback, false); |
| mptcp_stop_tout_timer(sk); |
| return 0; |
| |
| failed_unlink: |
| list_del(&subflow->node); |
| sock_put(mptcp_subflow_tcp_sock(subflow)); |
| |
| failed: |
| subflow->disposable = 1; |
| sock_release(sf); |
| |
| err_out: |
| /* we account subflows before the creation, and this failures will not |
| * be caught by sk_state_change() |
| */ |
| mptcp_pm_close_subflow(msk); |
| return err; |
| } |
| |
| static void mptcp_attach_cgroup(struct sock *parent, struct sock *child) |
| { |
| #ifdef CONFIG_SOCK_CGROUP_DATA |
| struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data, |
| *child_skcd = &child->sk_cgrp_data; |
| |
| /* only the additional subflows created by kworkers have to be modified */ |
| if (cgroup_id(sock_cgroup_ptr(parent_skcd)) != |
| cgroup_id(sock_cgroup_ptr(child_skcd))) { |
| #ifdef CONFIG_MEMCG |
| struct mem_cgroup *memcg = parent->sk_memcg; |
| |
| mem_cgroup_sk_free(child); |
| if (memcg && css_tryget(&memcg->css)) |
| child->sk_memcg = memcg; |
| #endif /* CONFIG_MEMCG */ |
| |
| cgroup_sk_free(child_skcd); |
| *child_skcd = *parent_skcd; |
| cgroup_sk_clone(child_skcd); |
| } |
| #endif /* CONFIG_SOCK_CGROUP_DATA */ |
| } |
| |
| static void mptcp_subflow_ops_override(struct sock *ssk) |
| { |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| if (ssk->sk_prot == &tcpv6_prot) |
| ssk->sk_prot = &tcpv6_prot_override; |
| else |
| #endif |
| ssk->sk_prot = &tcp_prot_override; |
| } |
| |
| static void mptcp_subflow_ops_undo_override(struct sock *ssk) |
| { |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| if (ssk->sk_prot == &tcpv6_prot_override) |
| ssk->sk_prot = &tcpv6_prot; |
| else |
| #endif |
| ssk->sk_prot = &tcp_prot; |
| } |
| |
| int mptcp_subflow_create_socket(struct sock *sk, unsigned short family, |
| struct socket **new_sock) |
| { |
| struct mptcp_subflow_context *subflow; |
| struct net *net = sock_net(sk); |
| struct socket *sf; |
| int err; |
| |
| /* un-accepted server sockets can reach here - on bad configuration |
| * bail early to avoid greater trouble later |
| */ |
| if (unlikely(!sk->sk_socket)) |
| return -EINVAL; |
| |
| err = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP, &sf); |
| if (err) |
| return err; |
| |
| lock_sock_nested(sf->sk, SINGLE_DEPTH_NESTING); |
| |
| err = security_mptcp_add_subflow(sk, sf->sk); |
| if (err) |
| goto err_free; |
| |
| /* the newly created socket has to be in the same cgroup as its parent */ |
| mptcp_attach_cgroup(sk, sf->sk); |
| |
| /* kernel sockets do not by default acquire net ref, but TCP timer |
| * needs it. |
| * Update ns_tracker to current stack trace and refcounted tracker. |
| */ |
| __netns_tracker_free(net, &sf->sk->ns_tracker, false); |
| sf->sk->sk_net_refcnt = 1; |
| get_net_track(net, &sf->sk->ns_tracker, GFP_KERNEL); |
| sock_inuse_add(net, 1); |
| err = tcp_set_ulp(sf->sk, "mptcp"); |
| if (err) |
| goto err_free; |
| |
| mptcp_sockopt_sync_locked(mptcp_sk(sk), sf->sk); |
| release_sock(sf->sk); |
| |
| /* the newly created socket really belongs to the owning MPTCP master |
| * socket, even if for additional subflows the allocation is performed |
| * by a kernel workqueue. Adjust inode references, so that the |
| * procfs/diag interfaces really show this one belonging to the correct |
| * user. |
| */ |
| SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino; |
| SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid; |
| SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid; |
| |
| subflow = mptcp_subflow_ctx(sf->sk); |
| pr_debug("subflow=%p", subflow); |
| |
| *new_sock = sf; |
| sock_hold(sk); |
| subflow->conn = sk; |
| mptcp_subflow_ops_override(sf->sk); |
| |
| return 0; |
| |
| err_free: |
| release_sock(sf->sk); |
| sock_release(sf); |
| return err; |
| } |
| |
| static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk, |
| gfp_t priority) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| struct mptcp_subflow_context *ctx; |
| |
| ctx = kzalloc(sizeof(*ctx), priority); |
| if (!ctx) |
| return NULL; |
| |
| rcu_assign_pointer(icsk->icsk_ulp_data, ctx); |
| INIT_LIST_HEAD(&ctx->node); |
| INIT_LIST_HEAD(&ctx->delegated_node); |
| |
| pr_debug("subflow=%p", ctx); |
| |
| ctx->tcp_sock = sk; |
| WRITE_ONCE(ctx->local_id, -1); |
| |
| return ctx; |
| } |
| |
| static void __subflow_state_change(struct sock *sk) |
| { |
| struct socket_wq *wq; |
| |
| rcu_read_lock(); |
| wq = rcu_dereference(sk->sk_wq); |
| if (skwq_has_sleeper(wq)) |
| wake_up_interruptible_all(&wq->wait); |
| rcu_read_unlock(); |
| } |
| |
| static bool subflow_is_done(const struct sock *sk) |
| { |
| return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE; |
| } |
| |
| static void subflow_state_change(struct sock *sk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| struct sock *parent = subflow->conn; |
| struct mptcp_sock *msk; |
| |
| __subflow_state_change(sk); |
| |
| msk = mptcp_sk(parent); |
| if (subflow_simultaneous_connect(sk)) { |
| mptcp_do_fallback(sk); |
| pr_fallback(msk); |
| subflow->conn_finished = 1; |
| mptcp_propagate_state(parent, sk, subflow, NULL); |
| } |
| |
| /* as recvmsg() does not acquire the subflow socket for ssk selection |
| * a fin packet carrying a DSS can be unnoticed if we don't trigger |
| * the data available machinery here. |
| */ |
| if (mptcp_subflow_data_available(sk)) |
| mptcp_data_ready(parent, sk); |
| else if (unlikely(sk->sk_err)) |
| subflow_error_report(sk); |
| |
| subflow_sched_work_if_closed(mptcp_sk(parent), sk); |
| |
| /* when the fallback subflow closes the rx side, trigger a 'dummy' |
| * ingress data fin, so that the msk state will follow along |
| */ |
| if (__mptcp_check_fallback(msk) && subflow_is_done(sk) && msk->first == sk && |
| mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) |
| mptcp_schedule_work(parent); |
| } |
| |
| void mptcp_subflow_queue_clean(struct sock *listener_sk, struct sock *listener_ssk) |
| { |
| struct request_sock_queue *queue = &inet_csk(listener_ssk)->icsk_accept_queue; |
| struct request_sock *req, *head, *tail; |
| struct mptcp_subflow_context *subflow; |
| struct sock *sk, *ssk; |
| |
| /* Due to lock dependencies no relevant lock can be acquired under rskq_lock. |
| * Splice the req list, so that accept() can not reach the pending ssk after |
| * the listener socket is released below. |
| */ |
| spin_lock_bh(&queue->rskq_lock); |
| head = queue->rskq_accept_head; |
| tail = queue->rskq_accept_tail; |
| queue->rskq_accept_head = NULL; |
| queue->rskq_accept_tail = NULL; |
| spin_unlock_bh(&queue->rskq_lock); |
| |
| if (!head) |
| return; |
| |
| /* can't acquire the msk socket lock under the subflow one, |
| * or will cause ABBA deadlock |
| */ |
| release_sock(listener_ssk); |
| |
| for (req = head; req; req = req->dl_next) { |
| ssk = req->sk; |
| if (!sk_is_mptcp(ssk)) |
| continue; |
| |
| subflow = mptcp_subflow_ctx(ssk); |
| if (!subflow || !subflow->conn) |
| continue; |
| |
| sk = subflow->conn; |
| sock_hold(sk); |
| |
| lock_sock_nested(sk, SINGLE_DEPTH_NESTING); |
| __mptcp_unaccepted_force_close(sk); |
| release_sock(sk); |
| |
| /* lockdep will report a false positive ABBA deadlock |
| * between cancel_work_sync and the listener socket. |
| * The involved locks belong to different sockets WRT |
| * the existing AB chain. |
| * Using a per socket key is problematic as key |
| * deregistration requires process context and must be |
| * performed at socket disposal time, in atomic |
| * context. |
| * Just tell lockdep to consider the listener socket |
| * released here. |
| */ |
| mutex_release(&listener_sk->sk_lock.dep_map, _RET_IP_); |
| mptcp_cancel_work(sk); |
| mutex_acquire(&listener_sk->sk_lock.dep_map, 0, 0, _RET_IP_); |
| |
| sock_put(sk); |
| } |
| |
| /* we are still under the listener msk socket lock */ |
| lock_sock_nested(listener_ssk, SINGLE_DEPTH_NESTING); |
| |
| /* restore the listener queue, to let the TCP code clean it up */ |
| spin_lock_bh(&queue->rskq_lock); |
| WARN_ON_ONCE(queue->rskq_accept_head); |
| queue->rskq_accept_head = head; |
| queue->rskq_accept_tail = tail; |
| spin_unlock_bh(&queue->rskq_lock); |
| } |
| |
| static int subflow_ulp_init(struct sock *sk) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| struct mptcp_subflow_context *ctx; |
| struct tcp_sock *tp = tcp_sk(sk); |
| int err = 0; |
| |
| /* disallow attaching ULP to a socket unless it has been |
| * created with sock_create_kern() |
| */ |
| if (!sk->sk_kern_sock) { |
| err = -EOPNOTSUPP; |
| goto out; |
| } |
| |
| ctx = subflow_create_ctx(sk, GFP_KERNEL); |
| if (!ctx) { |
| err = -ENOMEM; |
| goto out; |
| } |
| |
| pr_debug("subflow=%p, family=%d", ctx, sk->sk_family); |
| |
| tp->is_mptcp = 1; |
| ctx->icsk_af_ops = icsk->icsk_af_ops; |
| icsk->icsk_af_ops = subflow_default_af_ops(sk); |
| ctx->tcp_state_change = sk->sk_state_change; |
| ctx->tcp_error_report = sk->sk_error_report; |
| |
| WARN_ON_ONCE(sk->sk_data_ready != sock_def_readable); |
| WARN_ON_ONCE(sk->sk_write_space != sk_stream_write_space); |
| |
| sk->sk_data_ready = subflow_data_ready; |
| sk->sk_write_space = subflow_write_space; |
| sk->sk_state_change = subflow_state_change; |
| sk->sk_error_report = subflow_error_report; |
| out: |
| return err; |
| } |
| |
| static void subflow_ulp_release(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); |
| bool release = true; |
| struct sock *sk; |
| |
| if (!ctx) |
| return; |
| |
| sk = ctx->conn; |
| if (sk) { |
| /* if the msk has been orphaned, keep the ctx |
| * alive, will be freed by __mptcp_close_ssk(), |
| * when the subflow is still unaccepted |
| */ |
| release = ctx->disposable || list_empty(&ctx->node); |
| |
| /* inet_child_forget() does not call sk_state_change(), |
| * explicitly trigger the socket close machinery |
| */ |
| if (!release && !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, |
| &mptcp_sk(sk)->flags)) |
| mptcp_schedule_work(sk); |
| sock_put(sk); |
| } |
| |
| mptcp_subflow_ops_undo_override(ssk); |
| if (release) |
| kfree_rcu(ctx, rcu); |
| } |
| |
| static void subflow_ulp_clone(const struct request_sock *req, |
| struct sock *newsk, |
| const gfp_t priority) |
| { |
| struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk); |
| struct mptcp_subflow_context *new_ctx; |
| |
| if (!tcp_rsk(req)->is_mptcp || |
| (!subflow_req->mp_capable && !subflow_req->mp_join)) { |
| subflow_ulp_fallback(newsk, old_ctx); |
| return; |
| } |
| |
| new_ctx = subflow_create_ctx(newsk, priority); |
| if (!new_ctx) { |
| subflow_ulp_fallback(newsk, old_ctx); |
| return; |
| } |
| |
| new_ctx->conn_finished = 1; |
| new_ctx->icsk_af_ops = old_ctx->icsk_af_ops; |
| new_ctx->tcp_state_change = old_ctx->tcp_state_change; |
| new_ctx->tcp_error_report = old_ctx->tcp_error_report; |
| new_ctx->rel_write_seq = 1; |
| new_ctx->tcp_sock = newsk; |
| |
| if (subflow_req->mp_capable) { |
| /* see comments in subflow_syn_recv_sock(), MPTCP connection |
| * is fully established only after we receive the remote key |
| */ |
| new_ctx->mp_capable = 1; |
| new_ctx->local_key = subflow_req->local_key; |
| new_ctx->token = subflow_req->token; |
| new_ctx->ssn_offset = subflow_req->ssn_offset; |
| new_ctx->idsn = subflow_req->idsn; |
| |
| /* this is the first subflow, id is always 0 */ |
| subflow_set_local_id(new_ctx, 0); |
| } else if (subflow_req->mp_join) { |
| new_ctx->ssn_offset = subflow_req->ssn_offset; |
| new_ctx->mp_join = 1; |
| new_ctx->fully_established = 1; |
| new_ctx->remote_key_valid = 1; |
| new_ctx->backup = subflow_req->backup; |
| WRITE_ONCE(new_ctx->remote_id, subflow_req->remote_id); |
| new_ctx->token = subflow_req->token; |
| new_ctx->thmac = subflow_req->thmac; |
| |
| /* the subflow req id is valid, fetched via subflow_check_req() |
| * and subflow_token_join_request() |
| */ |
| subflow_set_local_id(new_ctx, subflow_req->local_id); |
| } |
| } |
| |
| static void tcp_release_cb_override(struct sock *ssk) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| long status; |
| |
| /* process and clear all the pending actions, but leave the subflow into |
| * the napi queue. To respect locking, only the same CPU that originated |
| * the action can touch the list. mptcp_napi_poll will take care of it. |
| */ |
| status = set_mask_bits(&subflow->delegated_status, MPTCP_DELEGATE_ACTIONS_MASK, 0); |
| if (status) |
| mptcp_subflow_process_delegated(ssk, status); |
| |
| tcp_release_cb(ssk); |
| } |
| |
| static int tcp_abort_override(struct sock *ssk, int err) |
| { |
| /* closing a listener subflow requires a great deal of care. |
| * keep it simple and just prevent such operation |
| */ |
| if (inet_sk_state_load(ssk) == TCP_LISTEN) |
| return -EINVAL; |
| |
| return tcp_abort(ssk, err); |
| } |
| |
| static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { |
| .name = "mptcp", |
| .owner = THIS_MODULE, |
| .init = subflow_ulp_init, |
| .release = subflow_ulp_release, |
| .clone = subflow_ulp_clone, |
| }; |
| |
| static int subflow_ops_init(struct request_sock_ops *subflow_ops) |
| { |
| subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock); |
| |
| subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name, |
| subflow_ops->obj_size, 0, |
| SLAB_ACCOUNT | |
| SLAB_TYPESAFE_BY_RCU, |
| NULL); |
| if (!subflow_ops->slab) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| void __init mptcp_subflow_init(void) |
| { |
| mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops; |
| mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4"; |
| mptcp_subflow_v4_request_sock_ops.destructor = subflow_v4_req_destructor; |
| |
| if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0) |
| panic("MPTCP: failed to init subflow v4 request sock ops\n"); |
| |
| subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops; |
| subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req; |
| subflow_request_sock_ipv4_ops.send_synack = subflow_v4_send_synack; |
| |
| subflow_specific = ipv4_specific; |
| subflow_specific.conn_request = subflow_v4_conn_request; |
| subflow_specific.syn_recv_sock = subflow_syn_recv_sock; |
| subflow_specific.sk_rx_dst_set = subflow_finish_connect; |
| subflow_specific.rebuild_header = subflow_rebuild_header; |
| |
| tcp_prot_override = tcp_prot; |
| tcp_prot_override.release_cb = tcp_release_cb_override; |
| tcp_prot_override.diag_destroy = tcp_abort_override; |
| |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| /* In struct mptcp_subflow_request_sock, we assume the TCP request sock |
| * structures for v4 and v6 have the same size. It should not changed in |
| * the future but better to make sure to be warned if it is no longer |
| * the case. |
| */ |
| BUILD_BUG_ON(sizeof(struct tcp_request_sock) != sizeof(struct tcp6_request_sock)); |
| |
| mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops; |
| mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6"; |
| mptcp_subflow_v6_request_sock_ops.destructor = subflow_v6_req_destructor; |
| |
| if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0) |
| panic("MPTCP: failed to init subflow v6 request sock ops\n"); |
| |
| subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; |
| subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req; |
| subflow_request_sock_ipv6_ops.send_synack = subflow_v6_send_synack; |
| |
| subflow_v6_specific = ipv6_specific; |
| subflow_v6_specific.conn_request = subflow_v6_conn_request; |
| subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; |
| subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; |
| subflow_v6_specific.rebuild_header = subflow_v6_rebuild_header; |
| |
| subflow_v6m_specific = subflow_v6_specific; |
| subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; |
| subflow_v6m_specific.send_check = ipv4_specific.send_check; |
| subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; |
| subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; |
| subflow_v6m_specific.rebuild_header = subflow_rebuild_header; |
| |
| tcpv6_prot_override = tcpv6_prot; |
| tcpv6_prot_override.release_cb = tcp_release_cb_override; |
| tcpv6_prot_override.diag_destroy = tcp_abort_override; |
| #endif |
| |
| mptcp_diag_subflow_init(&subflow_ulp_ops); |
| |
| if (tcp_register_ulp(&subflow_ulp_ops) != 0) |
| panic("MPTCP: failed to register subflows to ULP\n"); |
| } |